KCNMA1 and glioblastoma: As seen in Fig. 1A, the voltage-gated K+ current density in primary GBM cells is markedly increased in the presence of 1 μM intracellular Ca2+ (N=3, n=5) compared to Ca2+−free intracellular solution (N=5, n=11) which is characteristic of KCa1.1 channels (−40 mV, p=0.52; −20 mV, p=0.0004; 0 mV and above: p<0.0001, Student’s t tests).